The known method of producing bead-bead filler assemblies consists of producing metal beads, usually coated with elastomeric material, and, separately, an elongated extruded element of elastomeric material having a substantially triangular cross section, which is cut transversely into portions of the same length as the respective beads. Said bead filler portions are usually cut on a slant or angle so that each presents two opposed bevels which, when such a portion is placed or bent about its respective bead, are pressed together to produce a substantially continuous annular bead filler. Though successful, the above technique presents a number of drawbacks.
Firstly, being produced in sizable lots for subsequent application, at times even weeks after manufacture, sad elongated, substantially triangular-section element undergoes considerable uncontrolled shrinkage, with the result that the section of the bead filler varies from one lot to another.
Secondly, skilled labor and a good deal of time are required for cutting said elongated element into portions; applying each portion to the outer periphery of the bead; and connecting, usually by means of an adhesive, the opposite ends of each portion to form a respective bead filler.
Thirdly, the above known technique fails to provide for a jointfree bead-bead filler assembly, which joint, even if executed skillfully, invariably has a negative effect on the uniformity of the finished tire.
In regard to the uniformity of the finished tire, an important point to bear in mind is that, being originally straight, said bead filler portions preserve a tendency to revert to their original form, thus resulting in internal stress which tends to ovalize the finished bead-bead filler assembly.